1. Field of the Invention
The present invention relates to a stopper structure for use with a lens barrel assembly.
2. Description of the Related Art
Three-stage-extension zoom lens barrel assemblies are known as a common lens barrel structure for use in conventional zoom lenses of compact cameras. One type of such conventional three-stage-extension zoom lens barrel assemblies includes a fixed barrel secured to a camera body and two lens barrels retained within the fixed barrel. The fixed barrel and one of the two barrels that is directly inside the fixed barrel are connected to each other via helicoids whereas the other of the two barrels that is placed inside the first barrel is connected to the first barrel via a cam structure. Alternatively, some multi-stage-extension zoom lens barrel assemblies use a helicoid structure in all of the connections between lens barrels to move the connected lens barrels relative to each other.
These multi-stage-extension zoom lens barrel assemblies employ a stopper ring placed over a lens barrel for preventing lens barrels from being advanced past the normal operative position to come off the barrel assembly. When it is necessary to disassemble the barrel, however, the stopper ring must first be removed. This makes the disassembly process difficult.
In view of the above problem of the conventional multi-stage-extension zoom lens barrel assembly, a stopper structure is provided which can prevent the lens barrels from coming off and requires fewer components, thereby facilitating disassembly of the lens barrel assembly. A stopper structure is also provided for use in a lens barrel assembly which can prevent components of the lens barrel assembly, such as a flexible printed circuit board, from interfering with the stopper structure.
For example, in an embodiment, a stopper structure for use in a lens barrel assembly is provided, the lens barrel assembly including a helicoid ring, the helicoid ring including a male helicoid provided on an outer periphery of the helicoid ring for engaging with a female helicoid provided on an inner periphery of a fixed barrel secured to a camera body; and gear teeth formed along the male helicoids to extend between the male helicoids, the gear teeth being arranged in a circumferential direction about an optical axis, the helicoid ring moving along the optical axis while been driven by a pinion which is engaged with the gear teeth. The stopper structure includes a stopper member which engages with at least one tooth of the gear teeth in order to prevent rotation of the helicoid ring.
Rotation of the helicoid ring can be prevented when the helicoid ring advances as far as possible in the optical axis direction and the at least one tooth comes into engagement with the stopper member.
It is desirable for the stopper member to be removably attached to an outer surface of the fixed barrel.
It is desirable for a portion of the stopper member, which engages with the at least tooth of the gear teeth of the helicoid ring, to project into the fixed barrel.
An end tooth of the gear teeth can constitute the at least one tooth.
It is desirable for a stopper space to be provided in the vicinity of the end of the gear teeth to ensure a large contact width between the stopper member and the at least one tooth.
The stopper structure for use in a lens barrel assembly can further include a barrel which includes an electric member that moves along the optical axis without rotating as the helicoid ring rotates and moves along the optical axis; a flexible printed circuit board for connecting the shutter mechanism to an external control circuit arranged outside the lens barrel assembly, the circuit board including folds and being arranged along the optical axis and along an outer periphery of the helicoid ring; and an interference-preventing projection for sliding against the flexible printed circuit board to lift the flexible printed circuit in an outward radial direction, with respect to a rotational center of the barrel, in order to prevent the at least one tooth of the helicoid ring interfering with the flexible printed circuit board as the helicoid ring rotates and moves along the optical axis.
The electric member can be a shutter unit or a diaphragm unit.
The present disclosure relates to subject matter contained in Japanese Patent Application No. 2001-82093 (filed on Mar. 22, 2001) which is expressly incorporated herein by reference in its entirety.